Method for Chemically Cleaning Textile Material

ABSTRACT

The invention relates to a method for chemically cleaning textile material, characterized in that the textile material is treated with a compound of formula (1), 
     
       
         
         
             
             
         
       
     
     wherein R 1 , R 2 , R 3 , and R 4  identically or independently denote C 1  to C 22 -n- and/or iso-alkyl, C 5 - or C 6 -cycloalkyl, phenyl-C 1 -C 4 -alkyl, C 1 -C 9 -alkylphenyl or phenyl, A is (CH 2 ) a , and a is an integer from 0 to 6.

Washing with water and laundry detergents, within the home or in industrial and institutional laundries, is not the only important cleaning process applied to textiles. Dry cleaning is employed on water-sensitive textiles, but also in the case of stubborn soiling, especially oily and greasy stains.

Halogenated hydrocarbons are still being used as dry-cleaning medium. They include the hydrochlorocarbons trichloroethene, 1,1,1-trichloroethane and dichloromethane which are no longer permissible in Germany for example. Similarly, the chlorofluorocarbons (CFCs), which used to be widely used in dry cleaning, are no longer permitted for this application in many countries.

The solvent which is still being widely used is tetrachloroethene (perchloroethylene, perchlorethylene, perc, PER). Tetrachloroethene is a volatile chlorinated hydrocarbon which, by virtue of its fat-dissolving ability, has come to be widely used in industry, including dry cleaning, as a solvent/cleaner.

The disadvantages of PER are in particular its potential carcinogenic effect on humans; its high volatility; its ready solubility in fat-containing foods; and its strongly water-endangering properties.

PER is classified as dangerous in the EU's Black List and Germany's Haz Chem regulations.

Dry cleaning solvents, in particular perchloroethylene, pose dangers if allowed to pass into the environment. Potential sources of emissions are the cleaning machine, the drying air, the contact water, the distillation sludge, the textile material if inadequately dried and/or due to solvent retention, as well as accidents.

The control of the emission paths for organic solvents in the dry cleaning sector varies between different countries according to their environmental legislation and the degree to which their laws are observed and policed.

In Germany, dry cleaning operators and machine manufacturers have to meet a multiplicity of requirements to limit perchloroethylene emissions, such as maximum permissible values for PER emissions in the exit gas, in the drum region and in adjacent rooms, which entails a substantial engineering commitment.

However, irrespectively of the extent to which PER emissions are policed in dry cleaning establishments, appreciable amounts of PER may be retained in the most important textile substrates (wool, polyester) so that the emission of solvents by the textiles is important as well. In the case of PER, this can lead to indoor air exposures suffered by the consumer far away from the dry cleaning establishment.

The chlorofluorocarbons (CFCs) mentioned at the beginning, which are now no longer permitted in dry cleaning in most countries, made extremely low drying temperatures and, because of the high volatility, also short drying times and hence low mechanical stress on the textiles possible.

Irreversible damage to textiles bearing the care symbol “F” could thus reliably be avoided.

Halogen-free hydrocarbon solvents (HCS) have now been used for some time as technical alternatives to the banned CFCs as well as to the widely used PER. Originally, HCS solvents were only considered as a replacement for CFCs with regard to the cleaning of particularly sensitive textiles.

The HCS solvents are straight-chain aliphatics or mixtures of straight-chain, branched and cyclic aliphatics having 10 to 14 carbon atoms. Their higher boiling range from about 180 to 210° C. makes them distinctive from the petroleum fractions formerly likewise used in dry cleaning, or from perchloroethylene which has a boiling point of only 121° C. HCS solvents are widely used in dry cleaning in the US and Japan. However, one disadvantage with the use of HCS is that, as a consequence of the low vapor pressures, the drying temperatures have to be raised and/or the drying times distinctly extended. This imposes a distinctly greater thermal and mechanical stress on sensitive textiles, which shortens their useful consumer lives.

In addition, the energy requirements to distill and recycle HCS are distinctly higher compared with PER.

There is accordingly still a need for organic solvents which not only possess good cleaning power, but also can be deemed superior to the prior art in the eyes of toxicologists and ecologists and because of their physical-chemical properties.

Moreover, they should be substantially usable in the cleaning processes which the prior art employs for perchloroethylene (PER) and the hydrocarbon solvents (HCS).

The PER cleaning process consists of three stages:

-   1) The actual cleaning operation in a solvent bath which further     includes some water and cleaning boosters (comprising surfactants,     cosolvents and other components). -   2) The drying with hot air and the recovery of the solvent by     condensation and adsorption. -   3) The solvent regeneration through filtration and distillation, or     desorption.

The cleaning with HCS in principle involves the same stages as the PER cleaning process. The cleaning techniques on offer from various producers differ by separation of cleaning and drying (reloading technique), cleaning and drying being integrated in one machine (closed circuit) and also by inertization during cleaning and drying (nitrogen, combination of fresh air and circulating air or vacuum).

The following requirements should be at least substantially met by organic solvents contemplated as an alternative to perchloroethylene and/or to the hydrocarbon solvents: Good cleaning power in general and good ability to detach water-soluble or water-swellable soil and pigmentary soil, if appropriate through water-surfactant combinations (cleaning boosters); very good dissolving capacity for fats and oils; good dispersing capacity and sufficient dispersion stability for pigmentary soil to avoid graying; very little if any influencing of fibers, dyeings and finishes, i.e., only limited swelling of fibers, no adverse influence on the felting shrinkage of wool, negligible changes to the thermo-mechanical properties of fibers, no detachment of dyes, finishes, hotmelt adhesives, etc. (nor in the course of drying); very low retention in the fibrous substrate; no solvent odor in the cleaned textiles; a high volatility to facilitate drying and recovery; a sufficiently high flashpoint; little if any corrosivity toward metals and other materials of the cleaning and drying machines, not even in the presence of water; only minimal if any decomposition under cleaning and distillation conditions, i.e., in the presence of soil and at higher temperatures; low viscosity to facilitate soil detachment and for better mechanical removal of the solvent by centrifugation; low solubility in water but a certain amount of solvent power for water (if appropriate through the addition of surfactants and other solubilizers); dissolving power for so-called cleaning boosters (comprising for example nonionic, anionic, cationic, amphoteric surfactants, other solvents, for example (2-methoxymethylethoxy)propanol, specific salts, bleaching agents, disinfectants, antistats and other additives); formation of stable water-surfactant emulsions in the solvent; compliance with the maximum processing values mandated by the care-labeling scheme; and also low toxicity to humans and the environment.

The present invention has for its object to provide organic solvents which achieve the aforementioned dry cleaning requirements better than prior art solvents and which possess a better toxicological and ecological profile.

It has now been found that, surprisingly, compounds of the formula (1) possess superior cleaning or dissolving capacity for fats and oils and superior soil-suspending capacity and hence produce less graying and are judged as toxicologically and ecologically substantially more favorable than perchloroethylene and hydrocarbon solvents and in addition also fulfill the other aforementioned requirements and thus are very useful as dry cleaning medium.

The present invention accordingly provides for the use of compounds of the formula (1) as an organic cleaning agent and solvent in the dry cleaning of textiles

where where

-   A is (CH₂)_(a) or phenylene, -   R¹, R², R³ and R⁴ identically or independently denote C₁ to C₂₂-n-     and/or iso-alkyl, C₅- or C₆-cycloalkyl, phenyl-C₁-C₄-alkyl,     C₁-C₉-alkylphenyl or phenyl, -   and a is an integer from 0 to 6.

Preferably R¹, R², R³ and R⁴ identically or independently are C₁ to C₁₃-n- and/or iso-alkyl, C₅- or C₆-cycloalkyl, phenyl-C₁-C₂-alkyl, C₁-C₉-alkylphenyl or phenyl and a is an integer from 0 to 2.

More preferably, R¹ , R², R³ and R⁴ identically or independently are C₁ to C₈-n- and/or iso-alkyl, cyclohexyl, benzyl or phenyl and a is 0 or 1.

Most preferably, R¹, R², R³ and R⁴ identically or independently are C₁ to C₃-n- and/or iso-alkyl and a is 0.

Examples of the R¹ to R⁴ radicals are for example: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-amyl, isoamyl, tert-amyl, neopentyl, cyclopentyl, n-hexyl, isohexyl, cyclohexyl, octyl, decyl, isotridecyl, phenyl, benzyl, phenylethyl, nonylphenyl.

The compounds of the general formula (1) are acetals. Acetals are generally obtained by reaction of aldehydes with 2 mol of an alcohol per carbonyl group in the presence of catalysts, such as dry hydrogen chloride for example.

Dialdehydes have to be used to synthesize compounds of the formula (1). Preferred dialdehydes for synthesizing compounds of the formula (1) are glyoxal, malonaldehyde (1,3-propanedial, 1,3-propanedialdehyde), 1,4-butanedial and terephthalaldehyde. A greatly preferred dialdehyde is glyoxal, which leads to compounds of formula (1) where a=0.

A particularly preferred compound for the purpose described is tetramethoxyethane (2) from Clariant

and the analogous compound tetraethoxyethane

Compounds of the formula (1) can be utilized at various stages of the dry cleaning process, both in the industrial and institutional sector and in domestic dry cleaning. These include in particular the use as a dissolving and cleaning agent in the basic cleaning operation. Here, the compounds of the formula (1) can wholly replace the cleaning agents perchloroethylene, hydrocarbons and also other solvents.

The use of the solvents of the formula (1) can be effected in accordance with existing processes in so-called PER machines or in HCS machines (for example from Satec).

Representative processing conditions for using the compounds of the formula (1) are indicated by the hereinbelow described processing conditions for PER and HCS machines.

Process parameter PER machine HCS machine Speeds Cleaning 35 rpm 30-40 rpm Whizzing 380 rpm 700-800 rpm g-factor (whizzing) 77 330 Load 18 kg 18 kg Liquor ratio Low level 1:1.7 kg/l 1:3.9 kg/l High level 1:3.9 kg/l 1:6.7 kg/l Whirlbath — 1:6.7 kg/l Filter Centrifugal filters Cartridges Drying temperature 60° C. 70° C. Drying process Completion of drying process Nitrogen inertization at in-drum PER content Heating unlocked at of <2 g/m³ at fabric oxygen content <9% temperature of at least 35° C. Solvent distillation Under atmospheric max. −70 cm Hg pressure

Process modifications or modifications to the cleaning machines may be necessary, depending on the physical-chemical properties of specific compounds of the formula (1). For instance, different boiling points, due to different R¹ to R⁴ radicals and/or different a values, may necessitate different drying temperatures and, for example, variations in the distillation conditions to recover the solvent (pressure, temperature).

Flashpoints other than those of the HCS solvents used may also necessitate safety-engineering modifications, for example through the type of inertization (residual oxygen contents).

More particularly, the organic R radicals in the solvents of the formula 1 can be varied to control the dissolving power for apolar substances (other solvents, fats, oils) and also for polar substances and solvents (including water).

Different retentions and viscosities may also for example necessitate different g factors for whizzing off the solvent. In commercial practice, HCS machines utilize higher g factors than PER machines.

Further factors which may be altered/optimized through the use of solvents of the formula (1) include, for example, cleaning time, liquor ratio, reversing rhythm, load level, identity and amount of cleaning booster used, application of a whirlbath through injection of an air-solvent mixture for gentle cleaning of sensitive textiles.

All such modifications to the conventional process of dry cleaning which are the result of using the novel solvents of the formula (1) are easily determined by one of ordinary skill in the art through preliminary tests.

Dry cleaning processes are further distinguished between the one bath process and the two bath process. Standard work is generally cleaned in the two bath process by employing a short liquor ratio in the first bath and a longer liquor ratio in the second bath. The first bath serves to detach the main soil. Solvents of the formula (1) can be used in the one bath process and in the two bath process.

But in principle it is also possible to combine cleaning agents of the formula (1) with perchloroethylene, hydrocarbons or other solvents and thus partially replace the traditional solvents.

As well as being used as “main cleaning agent” (for the basic cleaning operation), compounds of the formula (1) can also be utilized in spotting agents, in cleaning activators or in cleaning boosters. Spotting agents are used for spot removal from textiles in industrial textile cleaning. The following groups of spotting agents are distinguished:

-   1) Brushing agents are used for the prespotting of large soiled     areas of textiles. They are applied neat, with a soft brush or by     spraying, to the badly soiled areas prior to the basic cleaning     operation. -   2) Dedicated spotting agents are used to treat intensive specific     stains on textiles. They are applied directly to the stain, and     allowed to act thereon, prior to the basic cleaning operation. -   3) Postspotting agents are used after the basic cleaning operation,     to remove any stains remaining.

Cleaning activators are used to remove spots and may also comprise odor absorbents for example. They are applied in the pretreatment bath and, being soil dissolvers, obviate any brushing.

Cleaning boosters, being added to the organic solvent used as cleaning medium, are intended to enhance the cleaning performance and, more particularly, also to effect the detachment of water-soluble or water-swellable soils which are only sparingly soluble, if at all, in the organic solvent. Examples of such water-soluble compounds include gritting salt (NaCl in high purity or else in mixture with CaCl₂ or MgCl₂ sols) as used in winter to deice sidewalks and streets. They shall further remove insoluble, pigmentary soil and exhibit a pigment-dispersing capacity and so inhibit the redeposition of detached particulate soil. They further serve to avoid pilling and to improve fabric hand. Cleaning boosters typically comprise surfactants (in particular anionic, nonionic, amphoteric surfactants or else cationic surfactants), solvents, antistats, softeners or hand-improving additives and, if appropriate, specialty adds such as disinfectants and bleaching agents. Furthermore, the cleaning booster can be used to introduce small amounts of water into the cleaning bath that is emulsified into the organic solvents with the surfactants.

The cleaning agent bath, i.e., the solvent of the formula (1) used for the basic cleaning operation, the spotting agents, the cleaning activators and the cleaning boosters comprising solvent of the formula (1) may comprise the following further soil release enhancers.

Surfactants

Surfactants which may be used in addition to or in the cleaning agents of the formula (1), for example in tetramethoxyethane (2), are:

Anionic surfactants

Useful anionic surfactants include sulfates, sulfonates, carboxylates, phosphates and mixtures thereof. Suitable cations are alkali metals, for example sodium or potassium, or alkaline earth metals, for example calcium or magnesium, and also ammonium, substituted ammonium compounds, including mono-, di- or triethanolammonium cations, and mixtures thereof.

The following types of anionic surfactants are particularly preferred: alkyl ester sulfonates, alkyl sulfates, alkyl ether sulfates, alkylbenzenesulfonates, alkanesulfonates and soaps as described in what follows.

Alkyl ester sulfonates include linear esters of C₈-C₂ ₂-carboxylic acids (i.e., fatty acids) which are sulfonated with gaseous SO₃. Suitable starting materials are natural fats, such as tallow, coco oil and palm oil for example. But the carboxylic acids may also be synthetic in nature. Preferred alkyl ester sulfonates are compounds of the formula

where R¹ is a C₈-C₂₀-hydrocarbyl radical, preferably alkyl, and R is a C₁-C₆-hydrocarbyl radical, preferably alkyl. M represents a cation which forms a water-soluble salt with the alkyl ester sulfonate. Suitable cations are sodium, potassium, lithium or ammonium cations, such as monoethanolamine, diethanolamine and triethanolamine. Preferably, R¹ is C₁₀-C₁₆-alkyl and R is methyl, ethyl or isopropyl. Particular preference is given to methyl ester sulfonates wherein R¹ is C₁₀-C₁₆-alkyl.

Alkyl sulfates are salts or acids of the formula ROSO₃M, where R is a C₁₀-C₂₄-hydrocarbyl radical, preferably an alkyl or hydroxyalkyl radical having a C₁₀-C₂₀-alkyl component, more preferably a C₁₂-C₁₈ alkyl or hydroxyalkyl radical.

M is hydrogen or a cation, for example an alkali metal cation (examples being sodium, potassium, lithium) or ammonium or substituted ammonium, for example methyl-, dimethyl- and trimethylammonium cations and quaternary ammonium cations such as tetramethylammonium and dimethylpiperidinium cations and quaternary ammonium cations derived from alkylamines, such as ethylamine, diethylamine, triethylamine and mixtures thereof.

Alkyl ether sulfates are salts or acids of the formula RO(A)_(m)SO₃M, where R is an unsubstituted C₁₀-C₂₄-alkyl or hydroxyalkyl radical, preferably a C₁₂-C₂₀ alkyl or hydroxyalkyl radical, more preferably a C₁₂-C₁₈-alkyl or hydroxyalkyl radical. A is an ethoxy or propoxy unit, m is a number greater than 0, preferably between about 0.5 and about 6, and more preferably between about 0.5 and about 3, and M is a hydrogen atom or a cation, for example sodium, potassium, lithium, calcium, magnesium, ammonium or a substituted ammonium cation.

Specific examples of substituted ammonium cations are methyl-, dimethyl- and trimethylammonium and quaternary ammonium cations such as tetramethylammonium and dimethylpiperidinium cations and also those derived from alkylamines, such as ethylamine, diethylamine, triethylamine or mixtures thereof. Examples which may be mentioned are C₁₂- to C₁₈-fatty alcohol ether sulfates wherein the EO content is 1, 2, 2.5, 3 or 4 mol per mole of the fatty alcohol ether sulfate and wherein M is sodium or potassium.

The alkyl group in secondary alkanesulfonates may be either saturated or unsaturated, branched or linear and optionally hydroxy substituted. The sulfo group may be situated on any position of the carbon chain, although the primary methyl groups at either end of the chain do not possess any sulfonate groups.

The preferred secondary alkanesulfonates comprise linear alkyl chains having about 9 to 25 carbon atoms, preferably about 10 to about 20 carbon atoms and more preferably about 13 to 17 carbon atoms. The cation is for example sodium, potassium, ammonium, mono-, di- or triethanolammonium, calcium or magnesium, or mixtures thereof. Sodium is the preferred cation.

Secondary alkanesulfonate is obtainable under the trade name of Hostapur SAS (from Clariant).

As well as secondary alkanesulfonates primary alkanesulfonates can likewise be used in the washing compositions of the present invention. The preferred alkyl chains and cations are as for the secondary alkanesulfonates.

Useful anionic surfactants further include alkenyl- or alkylbenzenesulfonates. The alkenyl or alkyl group may be branched or linear and optionally hydroxyl substituted. The preferred alkylbenzenesulfonates comprise linear alkyl chains having about 9 to 25 carbon atoms and preferably from about 10 to about 13 carbon atoms; the cation is sodium, potassium, ammonium, mono-, di- or triethanolammonium, calcium or magnesium and mixtures thereof.

Magnesium is the preferred cation for mild surfactant systems, whereas sodium is the preferred cation for standard applications. The same applies to alkenylbenzenesulfonates.

The term “anionic surfactants” also comprehends olefinsulfonates, which are obtained by sulfonation of C₈-C₂₄-olefins and preferably C₁₄-C₁₆-α-olefins with sulfur trioxide and subsequent neutralization. Their method of production is such that these olefinsulfonates may comprise minor amounts of hydroxyalkanesulfonates and alkanedisulfonates.

Preferred anionic surfactants further include carboxylates, examples being fatty acid soaps and comparable surfactants. The soaps may be saturated or unsaturated and may comprise various substituents, such as hydroxyl groups or α-sulfonate groups. Preference is given to linear saturated or unsaturated hydrocarbyl radicals as a hydrophobic moiety having about 6 about 30 and preferably about 10 to about 18 carbon atoms.

Useful anionic surfactants further include salts of acylamino carboxylic acids, acyl sarcosinates formed by reaction of fatty acid chlorides with sodium sarcosinate in an alkaline medium; fatty acid-protein condensation products obtained by reaction of fatty acid chlorides with oligopeptides; salts of alkylsulfamido carboxylic acids; salts of alkyl and alkylaryl ether carboxylic acids; sulfonated polycarboxylic acids; alkyl and alkenyl glycerol sulfates such as oleyl glycerol sulfates, alkylphenol ether sulfates, alkyl phosphates, alkyl ether phosphates, isethionates, such as acyl isethionates, N-acyltaurides, alkyl succinates, sulfosuccinates, monoesters of sulfosuccinates (particularly saturated and unsaturated C₁₂-C₁₈ monoesters) and diesters of sulfosuccinates (particularly saturated and unsaturated C₁₂-C₁₈ diesters), acyl sarcosinates, sulfates of alkylpolysaccharides such as sulfates of alkylpolyglycosides, branched primary alkyl sulfates and alkyl polyethoxy carboxylates such as those of the formula RO(CH₂CH₂)_(k)CH₂COO⁻M⁺, where R is C₈ to C₂₂ alkyl, k is from 0 to 10 and M is a cation.

Nonionic Surfactants

Condensation products of aliphatic alcohols with about 1 to about 25 mol of ethylene oxide.

The alkyl chain of the aliphatic alcohols may be linear or branched, primary or secondary, and comprises in general from about 8 to about 22 carbon atoms. Particular preference is given to the condensation products of C₁₀- to C₂₀-alcohols with about 2 to about 18 mol of ethylene oxide per mole of alcohol. The alkyl chain may be saturated or else unsaturated. The alcohol ethoxylates may comprise the ethylene oxide in a narrow homolog distribution (“narrow range ethoxylates”) or in a broad homolog distribution (“broad range ethoxylates”). This class of product includes for example the Genapol® brands (from Clariant).

Condensation products of ethylene oxide with a hydrophobic base, formed by condensation of propylene oxide with propylene glycol.

The hydrophobic part of these compounds preferably has a molecular weight between about 1500 and about 1800. The addition of ethylene oxide onto this hydrophobic part leads to improved solubility in water. The product is liquid up to a polyoxyethylene content of about 50% of the overall weight of the condensation product, which corresponds to a condensation with up to about 40 mol of ethylene oxide. Commercially available examples of this class of products are the ®Genapol PF brands (from Clariant).

Condensation Products of Ethylene Oxide with a Reaction Product of Propylene Oxide and Ethylenediamine.

The hydrophobic unit of these compounds consists of the reaction product of ethylenediamine with excess propylene oxide and generally has a molecular weight in the range of about 2500 to 3000. Ethylene oxide is added onto this hydrophobic unit up to a level of about 40% to about 80% by weight of polyoxyethylene and a molecular weight of about 5000 to 11 000. Commercially available examples of this class of compounds are the ®Tetronic brands from BASF and the ®Genapol PN brands from Clariant GmbH.

Semipolar Nonionic Surfactants

This category of nonionic compounds comprises water-soluble amine oxides, water-soluble phosphine oxides and water-soluble sulfoxides, each having an alkyl radical of about 10 to about 18 carbon atoms. Semipolar nonionic surfactants further include amine oxides of the formula

where R is an alkyl, hydroxyalkyl or alkylphenol group having a chain length of about 8 to about 22 carbon atoms, R² is an alkylene or hydroxyalkylene group having about 2 to 3 carbon atoms or mixtures thereof, every R¹ radical is an alkyl or hydroxyalkyl group having about 1 to about 3 carbon atoms or a polyethylene oxide group having about 1 to about 3 ethylene oxide units and x is from 0 to about 10. The R¹ groups may be joined together via an oxygen or nitrogen atom and thus form a ring. Amine oxides of this kind are particularly C₁₀-C₁₈-alkyldimethylamine oxides and C₈-C₁₂-alkoxyethyldihydroxyethylamine oxides.

Fatty Acid Amides

Fatty acid amides have the formula

where R is an alkyl group having about 7 to about 21 and preferably about 9 to about 17 carbon atoms and every R¹ radical is hydrogen, C₁-C₄-alkyl, C₁-C₄-hydroxyalkyl or (C₂H4O)_(x)H, where x varies from about 1 to about 3. C₈-C₂₀ amides, monoethanolamides, diethanolamides and isopropanolamides are preferred.

Useful nonionic surfactants further include alkyl and alkenyl oligoglycosides and also fatty acid polyglycol esters or fatty amine polyglycol esters each having 8 to 20 and preferably 12 to 18 carbon atoms in the fatty alkyl moiety, alkoxylated triglycamides, mixed ethers or mixed formyls, alkyl oligoglycosides, alkenyl oligoglycosides, fatty acid N-alkyl glucamides, phosphine oxides, dialkyl sulfoxides and protein hydrolyzates.

Polyethylene, polypropylene and polybutylene oxide condensates of alkylphenols.

These compounds comprise the condensation products of alkylphenols having a C₆- to C₂₀-alkyl group, which may be either linear or branched, with alkene oxides. Preference is given to compounds having about 5 to about 25 mol of alkene oxide per mole of alkylphenol. Commercially available surfactants of this type are for example the ®Arkopal N brands (from Clariant). These surfactants are referred to as alkylphenol alkoxylates, an example being alkylphenol ethoxylates.

Zwitterionic Surfactants

Typical examples of amphoteric or zwitterionic surfactants are alkyl betaines, alkylamide betaines, aminopropionates, aminoglycinates, or amphoteric imidazolinium compounds of the formula

where R¹ denotes C₈-C₂₂-alkyl or -alkenyl, R² denotes hydrogen or CH₂CO₂M, R³ denotes CH₂CH₂OH or CH₂CH₂OCH₂CH₂CO₂M, R⁴ denotes hydrogen, CH₂CH₂OH or CH₂CH₂COOM, Z denotes CO₂M or CH₂CO₂M, n denotes 2 or 3, preferably 2, M denotes hydrogen or a cation such as alkali metal, alkaline earth metal, ammonium or alkanolammonium.

Preferred amphoteric surfactants of this formula are monocarboxylates and dicarboxylates. Examples thereof are cocoamphocarboxypropionate, cocoamido carboxy propionic acid, cocoamphocarboxyglycinate (or else referred to as cocoamphodiacetate) and cocoamphoacetate.

Preferred amphoteric surfactants further include alkyl dimethyl betaines (®Genagen LAB/Clariant GmbH) and alkyl dipolyethoxy betaines having an alkyl radical of about 8 to about 22 carbon atoms, which may be linear or branched, preferably 8 to 18 carbon atoms and more preferably having about 12 to about 18 carbon atoms.

Useful cationic surfactants include substituted or unsubstituted straight-chain or branched quaternary ammonium salts of the type R¹N(CH₃)₃ ⁺X⁻, R¹R²N(CH₃)₂ ⁺X⁻, R¹R²R³ N(CH₃)⁺X⁻ or R¹R²R³R⁴N⁺X⁻. The R¹, R², R³ and R⁴ radicals may preferably independently be unsubstituted alkyl having a chain length of between 8 and 24 carbon atoms and especially between 10 and 18 carbon atoms, hydroxyalkyl having about 1 to about 4 carbon atoms, phenyl, C₂- to C₁₈-alkenyl such as, for example, tallow alkyl or oleyl, C₇- to C₂₄-aralkyl, (C₂H₄O )_(x)H, where x is from about 1 to about 3, or else alkyl radicals comprising one or more ester groups, or cyclic quaternary ammonium salts. X is a suitable anion.

As well as surfactants, further materials may be present: odor absorbents, deodorants, scents, antistats, microbicides such as bactericides and fungicides, preservatives, solubilizers, fiber regenerants, finishes, emulsifiers, enzymes, impregnants and also water in small amounts.

EXAMPLES

The hereinbelow described investigations were carried out using tetramethoxyethane (TME) of the formula (2) as an example of a solvent of the formula (1).

The following were utilized as references:

-   tetrachlorethene (=perchloroethylene, =PER) -   C₁₀₋₁₃ isoalkanes (=hydrocarbon solvent=HCS)

Example 1

The power to remove a liquid paraffin stain from various Wäschereiforschunganstalt Krefeld laundry research institute standard test fabrics was investigated.

The test fabrics used were:

-   cotton wfk 10A, cotton-polyester wfk 20A, polyester wfk 30A,     polyamide wfk 40A, acrylic wfk 50A, wool wfk 60A and silk wfk 70A.

These test fabrics were each soiled with paraffin oil colored with the fat-soluble dye Sudan Red. The reflectance (whiteness) of the soiled fabrics was measured. The test fabrics were then washed with tetramethoxyethane and the reference solvents at room temperature in a Linitest laboratory washing machine. For each type of fabric the wash included an unstained white fabric of the same type in order that the soil transfer/redeposition may be investigated. After the wash, the test fabrics were dried and assessed as follows.

To quantify soil release, the reflectance (whiteness) of the cleaned fabrics was determined and the difference to the values measured for the soiled fabrics was calculated.

The higher the dR reflectance values, the better the removal of the test soil. To determine soil redeposition, the L,a,b values of the adjacent white fabrics before and after the wash were compared to calculate the color difference dE.

The lower the color difference dE, the less the swatches were stained by soil transfer (redeposition).

TABLE 1 Removal of paraffin oil by tetramethoxyethane compared with PER and HSC dR whiteness (%) after cleaning with . . . Test fabric tetramethoxyethane PER HCS wfk 10A 47.1 45.8 38.6 wfk 20A 41.9 41.4 37.1 wfk 30A 38.2 36.8 36.4 wfk 40A 21.7 21.5 20.1 wfk 50A 40.9 39.5 39.6 wfk 60A 35.0 34.0 34.2 wfk 70A 28.0 26.3 27.6 Total (all fabrics) 252.8 245.3 233.6

TABLE 2 Staining dE of white fabrics by soil redeposition Staining dE of white fabrics by soil redeposition in . . . Test fabric tetramethoxyethane PER HCS wfk 10A 1.7 2.0 4.6 wfk 20A 1.7 2.1 2.6 wfk 30A 0.7 0.9 1.0 wfk 40A 2.2 2.2 3.2 wfk 50A 0.8 2.5 1.2 wfk 60A 3.0 3.5 1.0 wfk 70A 0.7 2.6 0.5 Total (all fabrics) 10.8 15.8 14.1

Example 2

The power to remove a vegetable oil stain from various Wäschereiforschungsanstalt Krefeld laundry research institute standard test fabrics was investigated. The vegetable oil used was sunflower oil, likewise colored with Sudan Red.

Procedure and analysis were similar to Example 1.

TABLE 3 Removal of sunflower oil by tetramethoxyethane compared with PER and HCS dR whiteness (%) after cleaning with . . . Test fabric tetramethoxyethane PER HCS wfk 10A 46.0 42.9 36.2 wfk 20A 43.3 41.3 38.3 wfk 30A 36.5 34.7 35.3 wfk 40A 21.1 19.8 19.9 wfk 50A 24.8 23.3 22.1 wfk 60A 17.0 17.1 17.6 wfk 70A 15.9 15.2 15.8 Total (all fabrics) 204.6 194.3 185.2

TABLE 4 Staining dE of white fabrics by soil redeposition Staining dE of white fabrics by soil redeposition in . . . Test fabric tetramethoxyethane PER HCS wfk 10A 1.8 2.4 4.0 wfk 20A 1.8 2.0 2.8 wfk 30A 0.8 1.2 1.0 wfk 40A 2.2 2.3 3.2 wfk 50A 0.7 1.8 1.4 wfk 60A 3.5 3.6 1.0 wfk 70A 0.6 1.6 0.8 Total (all fabrics) 11.4 14.9 14.2

Example 3

The cleaning power of tetramethoxyethane compared with PER and HCS was investigated on various standardized soiled fabrics from the Wäschereiforschungsanstalt Krefeld laundry research institute. The following test fabrics were used: cotton-polyester wfk 20C (blend fabric with fat-pigment soiling) and cotton-polyester wfk 20D (blend fabric with synthetic sebum soiling). The test fabrics were washed in a Linitest laboratory washing machine at room temperature. The wash included unsoiled cotton-polyester white fabric wfk 20A in order that the soil transfer from soiled to white test fabrics may be investigated.

The cleaning of the fabrics and the measurement-based quantification of the cleaning performance and of the soil transfer/graying were carried out as described in Example 1.

TABLE 5 Cleaning of standard test soil fabrics by tetramethoxyethane compared with PER and HCS dR (%) whiteness increase after cleaning with . . . Test fabric tetramethoxyethane PER HCS wfk 20C 17.9 13.7 17.2 wfk 20D 17.6 9.5 11.5 Total (all fabrics) 35.5 23.2 28.7

TABLE 6 Staining dE of white fabrics by soil redeposition White fabrics Staining dE of white fabrics washed in by soil deposition in . . . presence of . . . tetramethoxyethane PER HCS wfk 20C 4.3 9.2 5.9 wfk 20D 6.5 7.2 5.1 Total (all fabrics) 10.8 16.4 11.0

Example 4 Stability of Textile Dyeings

The stability of textile dyeings was tested on various commercially available colored fabrics. The colored fabrics were:

-   1. 100% polyamide, turquoise -   2. 100% polyester, royal blue -   3. 100% polyester, yellow -   4. 100% silk, bordeaux -   5. 100% silk, dark green -   6. 100% viscose, bordeaux -   7. 100% viscose, black -   8. 100% wool, ochre

Two swatches at a time of a colored fabric were washed together with 4 white swatches of the wfk 20A test fabric with tetramethoxyethane and the reference solvents in the Linitest washing machine at room temperature.

One of the colored swatches and two of the white swatches were removed after 10 min. The second colored swatch and the remaining two white swatches were each washed for another 50 minutes.

After drying, the colored fabrics and the white fabrics were assessed as follows. The color difference dE to the unwashed colored fabrics was determined to quantify the preservation of the color of the colored fabrics. The lower the dE color differences, the less the dyeings are attacked by the cleaning agent.

A possible color transfer due to detached dye was quantified by measuring the color different dE of the washed white swatches to the unwashed white fabric. The lower the dE value, the less the white fabrics were stained by the colored fabrics.

Ideally, the dE values are zero both for the preservation of color and for the transfer of color.

TABLE 7 Color preservation of various colored textiles after washing with tetramethoxyethane for 10 min compared with PER and HCS Color differences dE after a 10 min wash in . . . Colored fabric TME PER HCS 100% polyamide, turquoise 0.6 2.1 2.1 100% polyester, royal blue 0.2 0.4 0.2 100% polyester, yellow 0.9 1.4 1.0 100% silk, bordeaux 1.0 0.1 0.6 100% silk, dark green 0.4 0.2 0.3 100% viscose, bordeaux 1.0 0.9 1.1 100% viscose, black 0.6 1.1 0.8 100% wool, ochre 0.4 0.6 1.0 Total (all fabrics) 5.1 5.8 7.1

TABLE 8 Color preservation of various colored textiles after washing with tetramethoxyethane for 60 min compared with PER and HCS Color differences dE after a 60 min wash in . . . Colored fabric TME PER HCS 100% polyamide, turquoise 1.0 2.7 2.4 100% polyester, royal blue 0.4 0.4 0.3 100% polyester, yellow 1.2 1.5 1.5 100% silk, bordeaux 1.8 0.8 1.4 100% silk, dark green 0.6 1.3 0.4 100% viscose, bordeaux 2.6 0.9 2.3 100% viscose, black 0.7 1.1 1.2 100% wool, ochre 0.9 1.2 1.2 Total (all fabrics) 9.2 9.9 10.7

TABLE 9 Dye transfer to white fabric by washing with colored textiles in tetramethoxyethane for 10 min compared with PER and HCS Staining dE after White fabric washed in 10 min wash in . . . presence of colored fabric . . . TME PER HCS 100% polyamide, turquoise 4.4 4.5 3.5 100% polyester, royal blue 2.6 3.0 3.2 100% polyester, yellow 2.1 2.1 2.0 100% silk, bordeaux 2.8 3.0 2.9 100% silk, dark green 2.8 3.4 2.6 100% viscose, bordeaux 2.4 2.8 2.6 100% viscose, black 2.3 2.5 2.4 100% wool, ochre 2.5 52.9 2.8 Total (all fabrics) 21.9 24.2 22.0

TABLE 10 Dye transfer to white fabric by washing with colored textiles in tetramethoxyethane for 60 min compared with PER and HCS Staining dE after White fabric washed in 60 min wash in . . . presence of colored fabric . . . TME PER HCS 100% polyamide, turquoise 4.9 4.7 4.6 100% polyester, royal blue 2.6 3.0 3.2 100% polyester, yellow 2.1 2.1 2.2 100% silk, bordeaux 3.2 3.2 2.9 100% silk, dark green 2.9 3.6 2.8 100% viscose, bordeaux 3.0 3.4 2.7 100% viscose, black 2.4 2.7 2.7 100% wool, ochre 2.7 3.0 2.9 Total (all fabrics) 23.8 25.7 24.0 

1. A process for dry cleaning of textile material, which comprises treating the textile material with a compound of the formula (1)

where A is (CH₂)_(a) or phenylene, R¹, R², R³ and R⁴ identically or independently denote C₁ to C₂₂-normal or C₁ to C₂₂-iso-alkyl or mixtures of C₁ to C₂₂-normal and C₁ to C₂₂- iso-alkyl, C₅-cycloalkyl or C₆-cycloalkyl, phenyl-C₁-C₄-alkyl, C₁-C₈-alkylphenyl or phenyl, and a is an integer from 0 to
 6. 2. The process according to claim 1 wherein R¹, R², R³ and R⁴ identically or independently denote C₁ to C₁₃-normal alkyl or C₁ to C₁₃- iso-alkyl or mixtures of C₁ to C₁₃ normal-alkyl and iso-alkyl, C₅-cycloalkyl or C₆-cycloalkyl, phenyl-C₁-C₂-alkyl, C₁-C₉-alkylphenyl or phenyl and a denotes an integer from 0 to
 2. 3. The process according to claim 1 wherein the textile material is treated with a compound of the formula (1) where R¹, R², R³ and R⁴ identically or independently denote C₁ to C₈-normal or C₁ to C₈-iso-alkyl or mixtures of C₁ to C₈-normal C₁ to C₈-iso-alkyl, cyclohexyl, benzyl or phenyl and a denotes 0 or
 1. 4. The process according to claim 1 wherein the textile material is treated with a compound of the formula (1) where R¹, R², R³ and R⁴ identically or independently denote C₁ to C₃-normal C₁ to C₈-iso-alkyl or mixtures of C₁ to C₈-normal and C₁ to C₈-iso-alkyl and a denotes
 0. 5. (canceled)
 6. The process according to claim 1 wherein the compound of the formula (1) is a constituent of a spotting agent, of a cleaning booster or of a cleaning activator.
 7. The process according to claim 1 wherein the compound of the formula (1) is in combination with other components selected from the group consisting of anionic surfactants, nonionic surfactants, amphoteric surfactants, cationic surfactants, odor absorbents, deodorants, scents, antistats, microbicides, preservatives, solubilizers, fiber regenerants, finishes, emulsifiers, enzymes, impregnants and water in small amounts.
 8. The process according to claim 1 wherein R¹, R², R³ and R⁴ denote methyl or ethyl or a mixture of methyl and ethyl and a denotes
 0. 9. The process according to claim 1 wherein the process for dry cleaning of textiles is performed in the industrial and institutional sector.
 10. The process according to claim 1 wherein the process for dry cleaning of textiles is performed in the home.
 11. The process according to claim 1 where R¹, R², R³ and R⁴ contain different numbers of carbon atoms.
 12. The process according to claim 1 wherein the textile material is treated with two or more compounds of formula 1 which each of said compounds of formula 1 differ in the number of carbon atoms they contain.
 13. The process of claim 1, wherein the textile material is treated with the compound of formula (1) in combination with chloroethylene or a hydrocarbon or a mixture of chloroethylene and a hydrocarbon. 